Refrigerator/freezer thermal breaker

ABSTRACT

An efficient thermal breaker system for a refrigerator cabinet comprises a cabinet case with an opening and a cabinet liner separated from the cabinet case by thermal insulation. The thermal breaker system comprises a thermal breaker strip disposed between the cabinet case and the liner around the opening and a connecting corner piece affixed at a corner of the opening such that open space between neighboring end portions of thermal breaker strips is covered by the connecting corner piece with some overlapped portions. The thermal breaker system effectively prevents air leakage to the open space between the cabinet case and the liner around the opening.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a refrigerator and more particularly relates to a thermal breaker system.

[0003] 2. Description of Related Art

[0004] A thermal breaker is used in a refrigerator/freezer cabinet or a cabinet for an ice-making machine (hereinafter jointly “refrigerator cabinet”) to insulate the cooled inside air of the refrigerator cabinet from the leakage of warm outside ambient air when the cabinet door is closed. The thermal breaker is typically installed by screws or bolts after the interior is properly installed in the cabinet case. A thermal breaker may be formed in a shape to frame a door opening of the cabinet case (i.e., typically in a rectangular window frame shape) and may be assembled from parts of the thermal breaker.

[0005] Since it is not easy to make the thermal breaker in a complete door opening frame shape when the door opening is large, partially because the thermal breaker may be too big and easily deformed, it may be preferred to assemble the thermal breaker from its parts. However, that assembling process is complicated since it is usually required to use separate fastening tools such as screws in order to assemble the thermal breaker. Moreover, the size tolerance of each part must be small, and precise assembling is required to avoid unnecessary gaps and cracks among the parts, which may cause air leakage between joint parts.

[0006] Therefore, a need has developed for a more efficient thermal breaker easy to install for refrigerator cabinets with stainless steel or aluminum interiors.

SUMMARY OF THE INVENTION

[0007] The present invention provides an efficient thermal breaker system for a refrigerator cabinet comprising a cabinet case with a front opening and a liner disposed inside the cabinet case and separated from the cabinet case by thermal insulation. The thermal breaker system comprises a thermal breaker track having one or more corners and two or more sides, a first side of which is defined by the front panel and a second side of which is defined by the liner; a thermal breaker strip mounted on the thermal breaker track such that the thermal breaker strip separates the first side from the second side and covers space between the first and the second side; and a connecting corner piece mounted at a first corner of the thermal breaker track over the mounted thermal breaker strip such that part of the connecting corner piece overlaps with part of the mounted thermal breaker strip so as to cover space between the front panel and the liner around the first corner.

[0008] In another aspect according to the present invention, the thermal breaker track has four corners and four elongated parts in turn, which makes the door opening rectangular, square, or the like.

[0009] In yet another aspect according to the present invention, the thermal breaker track has a bridge member connecting the first side and the second side near the first corner. Therefore, the connecting corner piece may be fastened on the bridge member. The bridge member may comprise an opening where the connecting corner piece is fastened.

[0010] In another aspect according to the present invention, the thermal breaker strip has a first leg, which forms a first recess with a main body of the thermal breaker strip, and a second leg, which forms a second recess with the main body. The recesses ease the thermal breaker strip being affixed on the thermal breaker track.

[0011] In another aspect according to the present invention, the breaker track has a first breaker supporting part on the front panel side and a second breaker supporting part on the liner side; the first breaker supporting part being inserted in the first recess; and the second breaker supporting part being inserted in the second recess. Therefore, the thermal breaker strip is fixed on the thermal breaker track without any separate fastening tools such as screws and bolts.

[0012] In another aspect according to the present invention, the connecting corner piece has a fastening part to fasten the connecting corner piece on the thermal breaker track. The fastening part may have a saw-toothed part to latch the connecting corner piece. The fastening part may be inserted into an opening on the bridge member to work as a ratchet mechanism with an edge of the opening.

[0013] In another aspect according to the present invention, contacting surfaces of the overlapped parts of both connecting corner piece and mounted thermal breaker strip are smoothed so that air leakage between the contacting surfaces is prevented.

[0014] In another aspect according to the present invention, the overlapped parts of the connecting corner piece and the mounted thermal breaker strip are so thin that surface transition from the connecting corner piece to the thermal breaker strip is smooth. That is, a gap or step from the thermal breaker strip to the connecting corner piece is low.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a perspective view of a refrigerator cabinet with a door partially broken away, according to a first embodiment of the present invention.

[0016]FIG. 2 is an enlarged view of the upper-left corner of the opening shown in FIG. 1.

[0017]FIG. 3 shows a thermal breaker strip in a plan view and a cross sectional view.

[0018]FIG. 4 is a perspective view of a connecting corner piece in FIG. 4, according to the first embodiment of the present invention.

[0019]FIG. 5 is a perspective view by arrow B in FIG. 4.

[0020]FIG. 6 is a rear view by arrow C in FIG. 4.

[0021]FIG. 7 is a perspective view of a refrigerator cabinet with a door open, according to a second embodiment of the present invention.

[0022]FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 7.

[0023]FIG. 9 is a perspective view of a connection corner piece in FIG. 7, according to the second embodiment of the present invention.

[0024]FIG. 10 is a cross-sectional view taken along line 10-10 in FIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] With reference to the drawings, FIG. 1 shows a refrigerator cabinet 10 having a metallic cabinet case 12 and a door 14. The cabinet case 12 is typically made of steel or stainless steel (possibly made of other metal or other material). The cabinet case 12 is formed in a box shape with a top panel 16, a right panel 18, a bottom panel 20, a left panel 22, a back panel 24, and a front panel 26. Each panel is connected to adjacent panels at corresponding edges, which may be made by bending, welding, pressing in a drawing die, stamping, or any other plastic working method. The front panel 26 is connected to the top panel 16 at a top edge 28, to the right panel 18 at a right edge 30, to the bottom panel 20 at a bottom edge 32, and to the left panel 22 at a left edge 34. The front panel 26 has a front opening defined by a front panel top edge 36, a front panel right edge 38, a front panel bottom edge 40, and a front panel left edge 42. Each edge 36, 38, 40, 42 has a portion bent inwardly at a substantially right angle to the front panel 26 except around both ends of the edge. The bent portion will be described in detail later.

[0026] Inside the cabinet case 12, a liner 44, which may be typically made of metal such as steel, stainless steel, and aluminum, is disposed. The liner 44 is composed a liner top panel, a liner right panel, a liner bottom panel, a liner left panel, a liner back panel, and a liner front panel in a similar manner as the cabinet case 12 and is separated from the interior of the cabinet case by thermal insulation (not shown) such as foam. The liner front panel is also connected the liner top, right, bottom, and left panels in a similar manner and has a liner front opening coinciding with the front opening of the cabinet case 12. The liner front opening is defined by liner top, right, bottom, and left edges in a similar manner. Each edge of the liner top, right, bottom, and left edges has a portion bent outwardly at a substantially right angle to the liner front panel except around both ends of the edge. The liner front opening is equal or almost equal (or substantially equal) in size to the front opening in this embodiment. But the former may be smaller or larger than the latter.

[0027] Here, an opening defined by the front opening and the liner front opening may be called “door opening”. Thus, the door opening is framed by the front panel 26 and the liner front panel.

[0028] As shown in FIG. 1, the front panel 26 and the liner front panel are evenly or almost evenly (or substantially evenly) spaced from each other so as to form recessed area around the door opening. The recessed area may be filled with foam to insulate the liner 44 from the cabinet case 12. An imaginary rectangular flat face may be defined by one of the top, right, bottom, and left edges of the front panel 26 and corresponding one of the liner top, right, bottom, left edges of the liner front panel, so that the imaginary rectangular flat face contains the two edges at its front and back edges. Thus, the imaginary rectangular flat face defined by the top and the liner top edges, for example, may be called “imaginary top face”. And “imaginary right face”, “imaginary bottom face”, and “imaginary left face” may be named in such a manner.

[0029] The imaginary top face meets with the imaginary right face at the right edge of the imaginary top face, which coincides with the top edge of the imaginary right face. The two faces, therefore, make a right-and-top L-corner of the door opening over the right-and-top corner of the front panel 26 and the right-and-top corner of the liner front panel. Similarly, a right-and-bottom L-corner, a left-and-bottom L-corner, and a left-and-top L-corner are formed over both right-and-bottom corners, both left-and-bottom corners, and both left-and-top corners of the front panel 26 and the liner front panel, respectively.

[0030] Four thermal breaker strips 46, 48, 50, 52, which are rectangular or like a belt in the plan view, are mounted over the four imaginary faces. Thus, the imaginary faces define a thermal breaker track around the door opening such that one side of the thermal breaker track is defined by the front panel 26 and the other side of the thermal breaker track is defined by the liner 44 or the liner front panel. The thermal breaker track is substantially as wide as the thermal breaker strip and is looped around the door opening. A top thermal breaker strip 46 covers the top recessed area between the front panel top edge 36 and the liner top edge. A right thermal breaker strip 48 covers the right recessed area between the front panel right edge 38 and the liner right edge. A bottom thermal breaker strip 50 covers the bottom recessed area between the front panel bottom edge 40 and the liner bottom edge. A left thermal breaker strip 52 covers the left recessed area between the front panel left edge 42 and the liner left edge. Each thermal breaker strip is shorter than the corresponding imaginary face or the corresponding front panel edge and liner edge, so that at each L-corner of the door opening there is open space which is not covered with any thermal breaker strip as shown at the left-and-top L-corner of the door opening in FIG. 1. The details will be explained later.

[0031] A connecting corner piece 54 is provided to cover such open space at the left-and-top corner of the door opening as shown in FIG. 1. Connecting corner pieces 56, 58, 60 are provided at the right-and-top, right-and-bottom, and left-and-bottom corners, respectively. As shown in FIG. 1, the connecting corner pieces 54, 56, 58, 60 are mounted after all thermal breaker strips 46, 48, 50, 52 are installed.

[0032] The door 14 is connected to the cabinet case 12 with two hinges 62, 64 such that the door swings over the door opening. The door 14 has a gasket 66 to seal the refrigerator cabinet 10 from the ambient atmosphere. The gasket 66 comprises four elongated portions and four corners to form a rectangular circumferential embankment, which is larger than the door opening such that the inside of the cabinet case 12 may be sealed from the outside at the front face of the front panel 26. The gasket 66 may be made of resilient material with magnet inside so that the gasket 66 may be pressed against the front face of the front panel 26 with magnetic force when the door 14 is closed.

[0033]FIG. 2 shows an enlarged view of the left-and-top corner of the door opening with parts partially broken away. The cabinet case 12 has a case breaker support part 68, which is generally referred as an inwardly-bent portion above, extending from the left edge of the front panel 26. The case breaker support part 68 is an inwardly-bent portion at a substantially right angle to the front panel 26. Although the case breaker support part 68 does not exist near the L-corner, it extends along the front panel left edge 42 continuously (it may extend discontinuously). Similarly a case breaker support part 70, which is generally referred as an inwardly-bent portion above, extends along the front panel top edge 36 continuously (it may extend discontinuously). Thus, the inwardly-bent portions surround the door opening.

[0034] The liner front panel has a liner breaker support part 72, which is referred as an outwardly-bent portion above, extending from the liner left edge of the liner front panel in a similar manner. Although the liner breaker support part 72 does not exist near the L-corner, it extends along the liner left edge continuously (it may extend discontinuously). Similarly a liner breaker support part 74, which is generally referred as an outwardly-bent portion above, extends along the liner top edge continuously (it may extend discontinuously). Thus, the outwardly-bent portions surround the door opening.

[0035] The left thermal breaker strip 52 has a first leg 76 and a second leg 78 such that the case breaker support part 68 may be inserted into a first recess 80 made by the first leg 76 and a thermal breaker strip main body 82 and that the liner breaker support part 72 is inserted into a second recess 84 made by the second leg 78 and the thermal breaker strip main body 82. Thus, the left thermal breaker strip 52 can be mounted on the left case breaker support part 68 and that the left liner breaker support part 72 without any separate fastening means such as bolts, screws, etc. The other three thermal breaker strips 46, 48, 50 are similarly composed of the first leg and the second leg and mounted on the corresponding inwardly-bent and outwardly-bent portions.

[0036] The left thermal breaker strip 52 is installed in the following steps:

[0037] a. The left thermal breaker strip 52 is first provided on the left case breaker support part 68 and the liner breaker support part 72 such that the first leg 76 is positioned in the recessed opening between the left case and left liner breaker support parts 68, 72. The first leg 76 is positioned a little lower than the left case breaker support part 68.

[0038] b. The left thermal breaker strip 52 is then slid forward such that the left case breaker support 68 is inserted into the first recess 80.

[0039] c. The left thermal breaker strip 52 is further pushed forward and the left case breaker support part 68 is pushed deeper into the first recess 80 such that the second leg 78, which is originally positioned on the liner breaker support part 72, can be pushed down into the recessed area without any obstruction because the second leg 78 is no longer on the liner breaker support part 72.

[0040] d. The thermal breaker strip main body 82 is now mounted directly onto the left case breaker support part 68 and the liner breaker support part 72.

[0041] e. The left thermal breaker strip 52 is then pushed backward such that the liner breaker supporting part 72 is inserted into the second recess 84 until a front breaker side part 86 of the left thermal breaker strip 52 is aligned with the front panel left edge 42 (or a back breaker side part 87 is aligned with the liner left edge 43).

[0042] f. In a similar manner, the other three thermal breakers 46, 48, 50 are also mounted on the corresponding case and liner breaker support parts.

[0043] The top thermal breaker strip 46 is shown in FIG. 3. The other three thermal breaker strips 48, 50, 52 are identical or identical except the length. The thermal trip is rectangular in the plan view and has the two legs at any cross sectional view along the longitudinal direction of the strip.

[0044] Near the left-and-top L-corner of the door opening, the front panel 26 has a case bridge supporting part 88, which is bent inwardly at substantially right angle to the front panel 26. The liner front panel also has a liner bridge supporting part 90, which is bent outwardly at substantially right angel to the liner front panel 92, near the L-corner. On the case bridge supporting part 88 and the liner bridge support part 90, a rectangular bridge member 94 is mounted with rivets 96. The bridge member 94 has a rectangular opening around the center of the bridge member 94.

[0045] FIGS. 4-6 show the connecting corner piece 54, 56, 58, or 60, which has a fastening part 98 and an L-shaped main body with planer parts 100, 102 and an angled part 104. The fastening part 98 includes a stem 106 which is connected to the main body on the back side, tapered portions 108, 110 to a pointing edge 112, and a friction arm 114. The stem 106 has four ribs 116 for reinforcement. The tapered portions 120, 122 guide the fastening part 98 through a rectangular opening 124 into the right position. The friction arms 114, which can be compressed and expanded resiliently, has a saw-toothed part 126 on the outside so that the ratchet mechanism may work between the saw-toothed part 126 and short edges 128 of the rectangular opening 124. Therefore, the connecting corner piece 54, 56, 58, or 60 is fixed firmly once the fastening part 98 is inserted into the rectangular opening 124.

[0046] Referring back to FIG. 2, the left thermal breaker 52 is installed to prevent air leakage through open space 130 in the recessed area between the front panel 26 and the liner front panel 92. Thus, the main body 82 covers the open space 130 to block the air leakage and breaker side parts 132, 134 block side leakage. The engagement of the left case breaker support part 68 and the first recess 80 makes higher obstacle in an air leaking passage because gaps between the main body 82 and the left case breaker support part 68 and between the left case breaker support part 68 and the first leg 76 make a long and narrow path for air leakage.

[0047] The connecting corner piece 54, 56, 58, or 60 has the planar parts 100, 102 and side cover parts 136, 138 to block the air leakage in a similar manner. By way of example, the connecting corner piece 54 is mounted over the thermal breaker strips 52, 46 with overlapped parts 140, 142 at the top and left end portions of the thermal breaker strips 52, 46. Side faces 144, 146 around the top end portion of the thermal breaker strip 52 are brought into contact with bottom-side faces 148, 150 of the corner piece 54, respectively, as well as the overlapped part 140 with a bottom-flat face 152. The other side faces 154, 156 and the overlapped part 142 are also brought into contact with bottom-side faces 158, 160 and a bottom-flat face 162 of the connecting corner piece 54. All contacting faces or surfaces are smoothly finished such that air leakage may be effectively prevented. Any contacting parts of the thermal breaker and the connecting corner piece may be made thinner to make smooth transition surface from the corner piece to the thermal breaker strip.

[0048] Since the connecting corner pieces 54, 56, 58, 60 and the thermal breaker strips 46, 48, 50, 52 are typically made of resilient material such as plastic, contact pressure caused by elasticity applies to the contact surfaces in order to prevent air leakage. The saw-toothed parts 126 are latched on the short edges 128 such that the corner piece 54 may stay at the latched position against pulling-off or spring-back force and may not be snapped off from the left-and-top corner of the door opening once the corner piece 54 is firmly pressed such that the fastening part 98 is inserted into the rectangular opening 124 with elastic deformation of the corner piece 54. The spring-back force may cause contact pressure between the contacting surfaces in order to keep the gaps narrow enough to block the air leakage.

[0049] Similarly, the other connecting corner pieces 56, 58, 60 are mounted over the thermal breaker strips 46, 48, 50, 52.

[0050] In the first embodiment, the bridge member 94 is typically made of metal such as steel. However, the bridge member 94 may be made of plastic, engineering plastics, or other materials which may have lower thermal conductivity so as to prevent the bridge member 94 from serving a thermal bridge between the front panel 26 and the liner front panel 92.

[0051] After all thermal breaker strips are mounted as mentioned above steps a through f), the connecting corner pieces 54, 56, 58, 60 are mounted in the following steps. Although the corner piece 54 is, by way of example, first installed in the following steps, any one of the corner pieces 54, 56, 58, 60 may be installed in any order.

[0052] g. The corner piece 54 is held inside the door opening such that the fastening part 98 points the rectangular opening 124. In this particular case, the corner piece 54 is positioned inside the door opening with the bottom-flat face 162 horizontally along the thermal breaker strip 46 and with the bottom-flat face 152, to which the fastening part 98 is secured, disposed vertically to face the thermal breaker strip 52.

[0053] h. The corner piece 54 is slid along the thermal breaker strip 46 toward the left-and-top corner and the fastening part 98 is inserted into the rectangular opening 124. The corner piece 54 is further pushed to the left-and-top corner and the pushing force is removed after the saw-toothed parts are latched on the short edges 128.

[0054] i. The other corner pieces 56, 58, 60 are installed the other corners in a similar manner.

[0055] As described above, there is no separate fastening part required to install the thermal breaker strips and the connecting corner pieces (the thermal breaker system). Therefore, it is quite easy, quick, and efficient to install the thermal breaker system to the refrigerator cabinet. Further, the thermal breaker system does not require any special tools for installation so that the system can be assembled in any places such as the final user's site.

[0056] Since overlapped parts can be a little shorter or longer without losing the functions of the thermal breaker system, the thermal breaker strip may have a large tolerance so that the precise cut of the thermal breaker strip may not be required, which may reduce the cost for the thermal breaker system installation.

[0057]FIG. 7 shows another embodied refrigerator cabinet according to the present invention. The refrigerator cabinet 170 has a cabinet case 172 with a front opening at a front panel 174 and a door 176 connected to the cabinet case 172 with hinges 178. The front panel 174 frames the front opening such that top, right, bottom, and left edges 180, 182, 184, 186 define the front opening. The door 176 has a gasket 188. A liner 190, which is separated from the cabinet case 172 by thermal insulation 191, is disposed inside of the cabinet case 172. The liner is sized to match the front opening so that there is no front panel for the liner 190 unlike the first embodiment. The liner 190, thus, has a top, right, bottom, left edges around the front opening, each of which is formed substantially parallel to corresponding each of the four edges 180, 182, 184, 186.

[0058] Thus, four thermal breaker strips 192 are disposed between the front panel 174 of the cabinet case 172 and the front edges of the liner 190. At each corner of the front opening, a connecting corner piece 200 is installed to cover end portions of the thermal breaker strips such that air leakage is effectively prevented in a similar manner as mentioned above.

[0059]FIG. 8 shows a cross-sectional view taken along a line 8-8 of FIG. 7. The thermal breaker strip 192 has a first leg 202 and a second leg 204 and a main body with a planar portion and a round edge portion 206. The front portion of the cabinet case 172 is J-shaped in the cross sectional view. The cabinet case 172 is separated from the liner 192 by the thermal insulation 191 such as foam. The thermal breaker strip is mounted on a case breaker supporting part 208 and a liner breaker supporting part 210, which is front portion of the liner 190, in a similar manner as described before.

[0060]FIG. 9 shows the connecting corner piece 200 of FIG. 7. The connecting corner piece 200 is composed of a fastening part 212 and a main body with side covers 214, 216 and planar parts 218. The fastening part 212 has stoppers 220 to operate as a stud bolt when it is pushed into the insulation as shown in FIG. 10. Overlapping parts 222, 224, 226 with the thermal breaker strip 192 work as seal in a similar manner as described before. Unlike the first embodiment, there is no bridge member between the cabinet case 172 and the liner 190.

[0061] It should be understood that the foregoing relates only to preferred embodiments of the present invention, and thus changes and modifications thereto may be made without departing from the spirit and scope of the invention as defined in the following claims. 

What is claimed is:
 1. A thermal breaker system for a refrigerator cabinet having a cabinet case with a door opening framed by a front panel of the cabinet case and a liner disposed inside the cabinet case and separated from the cabinet case by insulation, the thermal breaker system comprising: a thermal breaker track having one or more corners and two or more sides, a first side of which is defined by the front panel and a second side of which is defined by the liner; a thermal breaker strip mounted on the thermal breaker track such that the thermal breaker strip separates the first side from the second side and covers space between the first and the second side; and a connecting corner piece mounted at a first corner of the thermal breaker track over the mounted thermal breaker strip such that part of the connecting corner piece overlaps with part of the mounted thermal breaker strip so as to cover space between the front panel and the liner around the first corner.
 2. The thermal breaker system of claim 1, wherein the thermal breaker track has four corners and four elongated parts in turn.
 3. The thermal breaker system of claim 1, wherein the thermal breaker track has a bridge member connecting the first side and the second side near the first corner.
 4. The thermal breaker system of claim 3, wherein the bridge member has an opening where the connecting corner piece is fastened.
 5. The thermal breaker system of claim 1, wherein the thermal breaker strip has a first leg, which forms a first recess with a main body of the thermal breaker strip, and a second leg, which forms a second recess with the main body.
 6. The thermal breaker system of claim 5, wherein the breaker track has a first breaker supporting part on the front panel side and a second breaker supporting part on the liner side the first breaker supporting part being inserted in the first recess; and the second breaker supporting part being inserted in the second recess.
 7. The thermal breaker system of claim 1, wherein the connecting corner piece has a fastening part to fasten the connecting corner piece on the thermal breaker track.
 8. The thermal breaker system of claim 7, wherein the fastening part has a saw-toothed part to latch the connecting corner piece.
 9. The thermal breaker system of claim 4, wherein the connecting corner piece has a fastening part to fasten the connecting corner piece by inserting the fastening part into the opening on the bridge member.
 10. The thermal breaker system of claim 9, wherein the fastening part has a saw-toothed part to operate as a ratchet mechanism with an edge of the opening on the bridge member.
 11. The thermal breaker system of claim 1, wherein surfaces of the overlapped parts of the connecting corner piece and the mounted thermal breaker strip are smoothed so that air leakage between the surfaces is prevented.
 12. The thermal breaker system of claim 1, wherein the overlapped parts of the connecting corner piece and the mounted thermal breaker strip are so thin that surface transition from the connecting corner piece to the thermal breaker strip is smooth.
 13. A refrigerator cabinet comprising: a cabinet case with a front opening framed by a front panel of the case; a door hingedly connected to the case cabinet, the door swinging over the front opening to cover the front opening; a looped gasket mounted on a back side of the door facing the front opening, the looped gasket being pressed against the front panel; a liner disposed inside the cabinet case, the liner being separated from the cabinet case by insulation; a thermal breaker track having one or more corners and two or more sides, a first side of which is defined by the front panel and a second side of which is defined by the liner; a thermal breaker strip mounted on the thermal breaker track such that the thermal breaker strip separates the first side from the second side and covers space between the first and the second side; and a connecting corner piece mounted at a first corner of the thermal breaker track over the mounted thermal breaker strip such that part of the connecting corner piece overlaps with part of the mounted thermal breaker strip so as to cover space between the front panel and the liner around the first corner.
 14. The refrigerator cabinet of claim 13, wherein the thermal breaker track has four corners and four elongated parts in turn.
 15. The refrigerator cabinet of claim 13, wherein the thermal breaker track has a bridge member connecting the first side and the second side near the first corner.
 16. The refrigerator cabinet of claim 13, wherein the thermal breaker strip has a first leg, which forms a first recess with a main body of the thermal breaker strip, and a second leg, which forms a second recess with the main body.
 17. The refrigerator cabinet of claim 13, wherein the connecting corner piece has a fastening part to fasten the connecting corner piece on the thermal breaker track.
 18. The refrigerator cabinet of claim 15, wherein the bridge member has an opening; and wherein the connecting corner piece has a fastening part to fasten the connecting corner piece by inserting the fastening part into the opening on the bridge member.
 19. The refrigerator cabinet of claim 18, wherein the fastening part has a saw-toothed part to operate as a ratchet mechanism with an edge of the opening on the bridge member
 20. The refrigerator cabinet of claim 13, wherein surfaces of the overlapped parts of the connecting corner piece and the mounted thermal breaker strip are smoothed so that air leakage between the surfaces is prevented.
 21. A connecting corner piece for a thermal breaker system including a first and a second thermal breaker strips and a receiving portion for the connecting corner piece, the connecting corner piece comprising: a main body being shaped to accord a thermal breaker track between the first and the second thermal breaker strips, the main body comprising a first overlap portion which overlaps with a part of the first thermal breaker strip and a second overlap portion which overlaps with a part of the second thermal breaker strip; and a fastening part being formed to engage with the receiving portion, the fastening part including a saw-toothed portion, the saw-toothed portion being mounted on an expanding-and-contracting porting of the fasting part such that the fastening part is latched in the receiving portion. 